| abstract |
The present invention relates to a melted and cast refractory product comprising, in mass percentages on the basis of the oxides and for a total of 100% of the oxides: ZrO 2 + Hf 2 O: 100% complement 4.5% <SiO 2 <7.0% Al 2 O 3 <0.85% 0.3% <B2O3 <1.5% Ta2O5 + Nb2O5 <0.2% Na2O + K2O <0.2% K2O <0.04% CaO + SrO + MgO + ZnO + BaO <0, 4% P205 <0.15% Fe203 + TiO2 <0.55% other oxide species: <1.5% the "A / B" ratio of the Al2O3 / B2O3 mass contents being between 0.5 and 2.0. Application to glass melting furnaces. |